Gesture With Machine Learning Users Guide

Table of Contents

Overview

This lab demonstrates the use of TI mmWave sensors for gesture recognition applications. The range, velocity, and angle data from mmWave sensors can enable the detection and classification of several natural gestures. The example provided in this demo can recoginize 9 distinct hand gestures: Left swipe, Right swipe, Up swipe, Down swipe, Clockwise twirl, Counterclockwise twirl, On gesture, Off gesture, and Shine gesture.

📝 NOTE This demo is compatible with both the xWR6443 and xWR6843, as it only uses the on-chip Hardware FFT acclerator (HWA) and does not utilize the on-chip c674x DSP. While this demo is intended for the xWR6443 device, a xWR6843 device can be used for emulation.

Requirements

Hardware Requirements

📝 NOTE Both AWR6843ISK-ODS and IWR6843ISK-ODS are supported and can be used interchangeably. Please consult the respective datasheets for details on the differences between the devices.

Software Requirements

Getting familiar with the device

⚠️ Run Out of Box Demo
Before continuing with this lab, users should first run the out of box demo for the EVM. This will enable users to gain familiarity with the sensor’s capabilities as well as the various tools used across all labs in the mmWave Toolbox.

Quickstart

1. Configure the EVM for Flashing Mode

• Follow the instructions for Hardware Setup of Flashing Mode

2. Flash the EVM using Uniflash

Flash the one of the binaries listed below using UniFlash. Follow the instructions for using UniFlash

• gesture_ML_6443_ODS.bin
• gesture_ML_6443_AOP.bin

Both binaries can be found at: <MMWAVE_TOOLBOX_INSTALL_DIR>\source\ti\examples\Gesture_Recognition\Gesture_with_Machine_Learning\prebuilt_binaries\

3. Configure the EVM for Functional Mode

• Follow the instructions for Hardware Setup of of Functional Mode

4. Run the Lab

1. GUI Setup

• Open a TeraTerm Instance for the User UART port as described below:
  • For Radar EVM only
    • USER UART = Silicon Labs Dual CP2105 USB to UART Bridge: Enhanced COM Port
  • For MMWAVEICBOOST + Radar EVM
    • USER UART = XDS110 Class Application/User UART
• TeraTerm (User UART): Go to Setup → Serial Port dialog and enter the COM Port number for the User UART Port and select the baud rate and other settings as shown below and press OK.

• Press Enter on the Control (User) UART terminal. You should see the mmWave:/> prompt which indicates that the demo started correctly. Please note that the gesture demo firmware auto-configures the sensor with pre-programmed chirp configuration at startup.
• The detected gesture output will be displayed on the User UART terminal. This demo also outputs the extracted features used for the nerual network inference as well as the raw neural network output probabilities for each gesture in a TLV structure to the Data UART port.

2. Running the Demo

This lab demonstrates the following features.

• Detection/Classification of nine gestures (within a range of about 0.3m): Right to Left Swipe, Left to Right Swipe, Up to Down Swipe, Down to Up Swipe, Clockwise Twirl, Counterclockwise Twirl, On Gesture, Off Gesture, Shine Gesture.

Perform the above gestures with your hand in front of sensor. The User UART terminal should show the corresponding output.

This concludes the Quickstart Section

Developer’s Guide

Import Lab Project to CCS

To import the source code into your CCS workspace, a CCS project is provided in the lab at the path given below.

• Start CCS and configure workspace as desired.

• Import the project specified below to CCS. <TOOLBOX_INSTALL_DIR>\source\ti\examples\Gesture_Recognition\Gesture_with_Machine_Learning\src\6443\gesture_ML_6443_ODS.projectspec or <TOOLBOX_INSTALL_DIR>\source\ti\examples\Gesture_Recognition\Gesture_with_Machine_Learning\src\6443\gesture_ML_6443_AOP.projectspec

• Verify that the import occurred without error by checking that gesture_ML_6443_ODS or gesture_ML_6443_AOP shows up in the project explorer

🛑 Error during Import to IDE
If an error occurs, check that the software dependencies listed above have been installed. Errors will occur if necessary files are not installed in the correct location for importing.

Build the Lab

• Select the gesture_ML_6443_ODS or gesture_ML_6443_AOP in Project Explorer so that it is highlighted. Right click on the project and select Rebuild Project. The project will then build.
• On successful build, the following should appear:
  • In <PROJECT_WORKSPACE_DIR>\gesture_ML_6443_ODS→Debug
    • gesture_ML_6443_ODS.xer4f (this is the Cortex R4F binary used for CCS debug mode)
    • gesture_ML_6443_ODS.bin (this is the flashable binary used for deployment mode)

Selecting Rebuild instead of Build ensures that the project is always re-compiled. This is especially important in case the previous build failed with errors.

🛑 Build Fails with Errors
If the build fails with errors, please ensure that all the software requirements are installed as listed above and in the mmWave SDK release notes.

📝 NOTE
As mentioned in the Quickstart section, pre-built binary files, both debug and deployment binaries are provided in the pre-compiled directory of the lab.

Execute the Lab

There are two ways to execute the compiled code on the EVM:

• Deployment mode: the EVM boots from flash and starts running the bin image at power-up
  • Using Uniflash, flash the gesture_ML_6443_ODS.bin found at <PROJECT_WORKSPACE_DIR>\gesture_ML_6443_ODS\Debug
  • The same procedure for flashing can be used as detailed in the Flash the EVM section.
• Debug mode: This mode is used for downloading and running the executable from CCS. This mode enables JTAG connection with CCS while the lab is running and is useful during development and debugging.
  • Follow the CCS Debug Mode Guide

UART Output Data Format

This demo outputs data using a TLV(type-length-value) encoding scheme with little endian byte order. For every frame, a packet is sent consisting of a fixed sized Frame Header and then a variable number of TLVs depending on what was detected in that scene. The TLVs for this demo include the extracted features used for the nerual network inference as well as the raw neural network output probabilities for each gesture.

Frame Header

Size: 40 bytes

frameHeaderStructType = struct(...
    'magicWord',                {'uint64', 8}, ... % syncPattern in hex is: '02 01 04 03 06 05 08 07' 
    'version',                  {'uint32', 4}, ... % Software Version
    'totalPacketLen',           {'uint32', 4}, ... % In bytes, including header
    'platform',                 {'uint32', 4}, ... % A6843
    'frameNumber',              {'uint32', 4}, ... % Frame Number
    'timeStamp',                {'uint32', 4}, ... % Message create time in cycles
    'numDetectedObj',           {'uint32', 4}, ... % Number of detected points in this frame
    'numTLVs' ,                 {'uint32', 4}, ... % Number of TLVs in this frame
    'subFrameNumber',           {'uint32', 4}, ... % Sub-Frame number

TLVs

The TLVs can be of type GESTURE FEATURES or ANN OUTPUT PROBABILITIES.

TLV Header

Size: 8 bytes

% TLV Type: 1020 = Point Cloud, 1010 = Target object list, 1011 = Target Index, 1012 = Target Height, 1021 = Presence Indication
tlvHeaderStruct = struct(...
    'type',             {'uint32', 4}, ... % TLV object 
    'length',           {'uint32', 4});    % TLV object Length, in bytes, including TLV header 

Following the header, is the the TLV-type specific payload

GESTURE FEATURES TLV

Size: sizeof (tlvHeaderStruct) + 40 bytes = 48 bytes

gestureFeatures = struct(...
    'weightedDoppler',              {'float', 4},
    'weightedPositiveDoppler',      {'float', 4},
    'weightedNegativeDoppler',      {'float', 4},
    'weightedRange',                {'float', 4}, 
    'numPoints',                    {'float', 4},
    'weightedAzimuthMean',          {'float', 4},
    'weightedElevationMean',        {'float', 4},
    'azimuthDopplerCorrelation',    {'float', 4},
    'weightedAzimuthDispersion',    {'float', 4},
    'weightedElevationDispersion',  {'float', 4});

ANN OUTPUT PROBABILITIES

Size: sizeof (tlvHeaderStruct) + 40 bytes = 48 bytes

outputProbs = struct(...
    'probabilityNoGesture',     {'float', 4},
    'probabilityGesture1',      {'float', 4},
    'probabilityGesture2',      {'float', 4},
    'probabilityGesture3',      {'float', 4}, 
    'probabilityGesture4',      {'float', 4},
    'probabilityGesture5',      {'float', 4},
    'probabilityGesture6',      {'float', 4},
    'probabilityGesture7',      {'float', 4},
    'probabilityGesture8',      {'float', 4},
    'probabilityGesture9',      {'float', 4});

Neural Network

This demo utilizes a neural network model which runs on the ARM core making predictions based on extracted features. A sliding window buffer of features, extracted from the data across a number of frames, is used as input to the neural network. The model outputs a set of probabilities, each represents the probability that the input data belongs to a specific gesture.

The model is implemented in the form of header files which contain the weight and bias values for each layer in the neural network. These header files can be found in src/6443/include/neuralnet/.

Features

The model is trained on following extracted features.

Layers

The structure of the neural network used in this demo can be seen in the diagram below. It consists of a 90 node input (6 features accumulated for the previous 15 frames), two hidden layers of size 30 and 60 respecfully, each with a rectified linear activation (ReLU), and finally a soft max function to convert to 10 output probabilities.

Retraining

Users may wish to retrain the neural network model for various reasons such as adding or removing certain gestures. The full process for retraining and deploying a model is not provided in this guide; however, one can save the extracted features which are output over UART and use the saved features as training data in the model building process.

Need More Help?

• Search for your issue or post a new question on the mmWave E2E forums
• See the SDK for more documentation on various algorithms used in this demo. Start at <mmWave_sdk_install_dir>/docs/mmwave_sdk_module_documentation.html